/*
 * ipcp.c - PPP IP Control Protocol.
 *
 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Office of Technology Transfer
 *      Carnegie Mellon University
 *      5000 Forbes Avenue
 *      Pittsburgh, PA  15213-3890
 *      (412) 268-4387, fax: (412) 268-7395
 *      tech-transfer@andrew.cmu.edu
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "netif/ppp/ppp_opts.h"
#if PPP_SUPPORT &&                                                             \
    PPP_IPV4_SUPPORT /* don't build if not configured for use in lwipopts.h */

/*
 * @todo:
 */

#if 0 /* UNUSED */
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/types.h>
#endif /* UNUSED */

#include "netif/ppp/ppp_impl.h"

#include "netif/ppp/fsm.h"
#include "netif/ppp/ipcp.h"

#if 0  /* UNUSED */
/* global vars */
u32_t netmask = 0;		/* IP netmask to set on interface */
#endif /* UNUSED */

#if 0  /* UNUSED */
bool	disable_defaultip = 0;	/* Don't use hostname for default IP adrs */
#endif /* UNUSED */

#if 0  /* moved to ppp_settings */
bool	noremoteip = 0;		/* Let him have no IP address */
#endif /* moved to ppp_setting */

#if 0  /* UNUSED */
/* Hook for a plugin to know when IP protocol has come up */
void (*ip_up_hook) (void) = NULL;

/* Hook for a plugin to know when IP protocol has come down */
void (*ip_down_hook) (void) = NULL;

/* Hook for a plugin to choose the remote IP address */
void (*ip_choose_hook) (u32_t *) = NULL;
#endif /* UNUSED */

#if PPP_NOTIFY
/* Notifiers for when IPCP goes up and down */
struct notifier *ip_up_notifier = NULL;
struct notifier *ip_down_notifier = NULL;
#endif /* PPP_NOTIFY */

/* local vars */
#if 0  /* moved to ppp_pcb */
static int default_route_set[NUM_PPP];	/* Have set up a default route */
static int proxy_arp_set[NUM_PPP];	/* Have created proxy arp entry */
static int ipcp_is_up;			/* have called np_up() */
static int ipcp_is_open;		/* haven't called np_finished() */
static bool ask_for_local;		/* request our address from peer */
#endif /* moved to ppp_pcb */
#if 0  /* UNUSED */
static char vj_value[8];		/* string form of vj option value */
static char netmask_str[20];		/* string form of netmask value */
#endif /* UNUSED */

/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void ipcp_resetci(fsm *f); /* Reset our CI */
static int ipcp_cilen(fsm *f);    /* Return length of our CI */
static void ipcp_addci(fsm *f, u_char *ucp, int *lenp); /* Add our CI */
static int ipcp_ackci(fsm *f, u_char *p, int len);      /* Peer ack'd our CI */
static int ipcp_nakci(fsm *f, u_char *p, int len,
                      int treat_as_reject);        /* Peer nak'd our CI */
static int ipcp_rejci(fsm *f, u_char *p, int len); /* Peer rej'd our CI */
static int ipcp_reqci(fsm *f, u_char *inp, int *len,
                      int reject_if_disagree); /* Rcv CI */
static void ipcp_up(fsm *f);                   /* We're UP */
static void ipcp_down(fsm *f);                 /* We're DOWN */
static void ipcp_finished(fsm *f);             /* Don't need lower layer */

static const fsm_callbacks ipcp_callbacks = {
    /* IPCP callback routines */
    ipcp_resetci,  /* Reset our Configuration Information */
    ipcp_cilen,    /* Length of our Configuration Information */
    ipcp_addci,    /* Add our Configuration Information */
    ipcp_ackci,    /* ACK our Configuration Information */
    ipcp_nakci,    /* NAK our Configuration Information */
    ipcp_rejci,    /* Reject our Configuration Information */
    ipcp_reqci,    /* Request peer's Configuration Information */
    ipcp_up,       /* Called when fsm reaches OPENED state */
    ipcp_down,     /* Called when fsm leaves OPENED state */
    NULL,          /* Called when we want the lower layer up */
    ipcp_finished, /* Called when we want the lower layer down */
    NULL,          /* Called when Protocol-Reject received */
    NULL,          /* Retransmission is necessary */
    NULL,          /* Called to handle protocol-specific codes */
    "IPCP"         /* String name of protocol */
};

/*
 * Command-line options.
 */
#if PPP_OPTIONS
static int setvjslots(char **);
static int setdnsaddr(char **);
static int setwinsaddr(char **);
static int setnetmask(char **);
int setipaddr(char *, char **, int);

static void printipaddr(option_t *, void (*)(void *, char *, ...), void *);

static option_t ipcp_option_list[] = {
    {"noip", o_bool, &ipcp_protent.enabled_flag, "Disable IP and IPCP"},
    {"-ip", o_bool, &ipcp_protent.enabled_flag, "Disable IP and IPCP",
     OPT_ALIAS},

    {"novj", o_bool, &ipcp_wantoptions[0].neg_vj, "Disable VJ compression",
     OPT_A2CLR, &ipcp_allowoptions[0].neg_vj},
    {"-vj", o_bool, &ipcp_wantoptions[0].neg_vj, "Disable VJ compression",
     OPT_ALIAS | OPT_A2CLR, &ipcp_allowoptions[0].neg_vj},

    {"novjccomp", o_bool, &ipcp_wantoptions[0].cflag,
     "Disable VJ connection-ID compression", OPT_A2CLR,
     &ipcp_allowoptions[0].cflag},
    {"-vjccomp", o_bool, &ipcp_wantoptions[0].cflag,
     "Disable VJ connection-ID compression", OPT_ALIAS | OPT_A2CLR,
     &ipcp_allowoptions[0].cflag},

    {"vj-max-slots", o_special, (void *)setvjslots,
     "Set maximum VJ header slots", OPT_PRIO | OPT_A2STRVAL | OPT_STATIC,
     vj_value},

    {"ipcp-accept-local", o_bool, &ipcp_wantoptions[0].accept_local,
     "Accept peer's address for us", 1},
    {"ipcp-accept-remote", o_bool, &ipcp_wantoptions[0].accept_remote,
     "Accept peer's address for it", 1},

    {"ipparam", o_string, &ipparam, "Set ip script parameter", OPT_PRIO},

    {"noipdefault", o_bool, &disable_defaultip,
     "Don't use name for default IP adrs", 1},

    {"ms-dns", 1, (void *)setdnsaddr, "DNS address for the peer's use"},
    {"ms-wins", 1, (void *)setwinsaddr,
     "Nameserver for SMB over TCP/IP for peer"},

    {"ipcp-restart", o_int, &ipcp_fsm[0].timeouttime, "Set timeout for IPCP",
     OPT_PRIO},
    {"ipcp-max-terminate", o_int, &ipcp_fsm[0].maxtermtransmits,
     "Set max #xmits for term-reqs", OPT_PRIO},
    {"ipcp-max-configure", o_int, &ipcp_fsm[0].maxconfreqtransmits,
     "Set max #xmits for conf-reqs", OPT_PRIO},
    {"ipcp-max-failure", o_int, &ipcp_fsm[0].maxnakloops,
     "Set max #conf-naks for IPCP", OPT_PRIO},

    {"defaultroute", o_bool, &ipcp_wantoptions[0].default_route,
     "Add default route", OPT_ENABLE | 1, &ipcp_allowoptions[0].default_route},
    {"nodefaultroute", o_bool, &ipcp_allowoptions[0].default_route,
     "disable defaultroute option", OPT_A2CLR,
     &ipcp_wantoptions[0].default_route},
    {"-defaultroute", o_bool, &ipcp_allowoptions[0].default_route,
     "disable defaultroute option", OPT_ALIAS | OPT_A2CLR,
     &ipcp_wantoptions[0].default_route},

    {"replacedefaultroute", o_bool, &ipcp_wantoptions[0].replace_default_route,
     "Replace default route", 1},
    {"noreplacedefaultroute", o_bool,
     &ipcp_allowoptions[0].replace_default_route, "Never replace default route",
     OPT_A2COPY, &ipcp_wantoptions[0].replace_default_route},
    {"proxyarp", o_bool, &ipcp_wantoptions[0].proxy_arp, "Add proxy ARP entry",
     OPT_ENABLE | 1, &ipcp_allowoptions[0].proxy_arp},
    {"noproxyarp", o_bool, &ipcp_allowoptions[0].proxy_arp,
     "disable proxyarp option", OPT_A2CLR, &ipcp_wantoptions[0].proxy_arp},
    {"-proxyarp", o_bool, &ipcp_allowoptions[0].proxy_arp,
     "disable proxyarp option", OPT_ALIAS | OPT_A2CLR,
     &ipcp_wantoptions[0].proxy_arp},

    {"usepeerdns", o_bool, &usepeerdns, "Ask peer for DNS address(es)", 1},

    {"netmask", o_special, (void *)setnetmask, "set netmask",
     OPT_PRIO | OPT_A2STRVAL | OPT_STATIC, netmask_str},

    {"ipcp-no-addresses", o_bool, &ipcp_wantoptions[0].old_addrs,
     "Disable old-style IP-Addresses usage", OPT_A2CLR,
     &ipcp_allowoptions[0].old_addrs},
    {"ipcp-no-address", o_bool, &ipcp_wantoptions[0].neg_addr,
     "Disable IP-Address usage", OPT_A2CLR, &ipcp_allowoptions[0].neg_addr},

    {"noremoteip", o_bool, &noremoteip, "Allow peer to have no IP address", 1},

    {"nosendip", o_bool, &ipcp_wantoptions[0].neg_addr,
     "Don't send our IP address to peer", OPT_A2CLR,
     &ipcp_wantoptions[0].old_addrs},

    {"IP addresses", o_wild, (void *)&setipaddr,
     "set local and remote IP addresses", OPT_NOARG | OPT_A2PRINTER,
     (void *)&printipaddr},

    {NULL}};
#endif /* PPP_OPTIONS */

/*
 * Protocol entry points from main code.
 */
static void ipcp_init(ppp_pcb *pcb);
static void ipcp_open(ppp_pcb *pcb);
static void ipcp_close(ppp_pcb *pcb, const char *reason);
static void ipcp_lowerup(ppp_pcb *pcb);
static void ipcp_lowerdown(ppp_pcb *pcb);
static void ipcp_input(ppp_pcb *pcb, u_char *p, int len);
static void ipcp_protrej(ppp_pcb *pcb);
#if PRINTPKT_SUPPORT
static int ipcp_printpkt(const u_char *p, int plen,
                         void (*printer)(void *, const char *, ...), void *arg);
#endif /* PRINTPKT_SUPPORT */
#if PPP_OPTIONS
static void ip_check_options(void);
#endif /* PPP_OPTIONS */
#if DEMAND_SUPPORT
static int ip_demand_conf(int);
static int ip_active_pkt(u_char *, int);
#endif /* DEMAND_SUPPORT */
#if 0  /* UNUSED */
static void create_resolv (u32_t, u32_t);
#endif /* UNUSED */

const struct protent ipcp_protent = {PPP_IPCP,
                                     ipcp_init,
                                     ipcp_input,
                                     ipcp_protrej,
                                     ipcp_lowerup,
                                     ipcp_lowerdown,
                                     ipcp_open,
                                     ipcp_close,
#if PRINTPKT_SUPPORT
                                     ipcp_printpkt,
#endif /* PRINTPKT_SUPPORT */
#if PPP_DATAINPUT
                                     NULL,
#endif /* PPP_DATAINPUT */
#if PRINTPKT_SUPPORT
                                     "IPCP",
                                     "IP",
#endif /* PRINTPKT_SUPPORT */
#if PPP_OPTIONS
                                     ipcp_option_list,
                                     ip_check_options,
#endif /* PPP_OPTIONS */
#if DEMAND_SUPPORT
                                     ip_demand_conf,
                                     ip_active_pkt
#endif /* DEMAND_SUPPORT */
};

static void ipcp_clear_addrs(ppp_pcb *pcb, u32_t ouraddr, u32_t hisaddr,
                             u8_t replacedefaultroute);

/*
 * Lengths of configuration options.
 */
#define CILEN_VOID 2
#define CILEN_COMPRESS 4 /* min length for compression protocol opt. */
#define CILEN_VJ 6       /* length for RFC1332 Van-Jacobson opt. */
#define CILEN_ADDR 6     /* new-style single address option */
#define CILEN_ADDRS 10   /* old-style dual address option */

#define CODENAME(x) ((x) == CONFACK ? "ACK" : (x) == CONFNAK ? "NAK" : "REJ")

#if 0  /* UNUSED, already defined by lwIP */
/*
 * Make a string representation of a network IP address.
 */
char *
ip_ntoa(ipaddr)
u32_t ipaddr;
{
    static char b[64];

    slprintf(b, sizeof(b), "%I", ipaddr);
    return b;
}
#endif /* UNUSED, already defined by lwIP */

/*
 * Option parsing.
 */
#if PPP_OPTIONS
/*
 * setvjslots - set maximum number of connection slots for VJ compression
 */
static int setvjslots(argv)
char **argv;
{
  int value;

  if (!int_option(*argv, &value))
    return 0;

  if (value < 2 || value > 16) {
    option_error("vj-max-slots value must be between 2 and 16");
    return 0;
  }
  ipcp_wantoptions[0].maxslotindex = ipcp_allowoptions[0].maxslotindex =
      value - 1;
  slprintf(vj_value, sizeof(vj_value), "%d", value);
  return 1;
}

/*
 * setdnsaddr - set the dns address(es)
 */
static int setdnsaddr(argv)
char **argv;
{
  u32_t dns;
  struct hostent *hp;

  dns = inet_addr(*argv);
  if (dns == (u32_t)-1) {
    if ((hp = gethostbyname(*argv)) == NULL) {
      option_error("invalid address parameter '%s' for ms-dns option", *argv);
      return 0;
    }
    dns = *(u32_t *)hp->h_addr;
  }

  /* We take the last 2 values given, the 2nd-last as the primary
     and the last as the secondary.  If only one is given it
     becomes both primary and secondary. */
  if (ipcp_allowoptions[0].dnsaddr[1] == 0)
    ipcp_allowoptions[0].dnsaddr[0] = dns;
  else
    ipcp_allowoptions[0].dnsaddr[0] = ipcp_allowoptions[0].dnsaddr[1];

  /* always set the secondary address value. */
  ipcp_allowoptions[0].dnsaddr[1] = dns;

  return (1);
}

/*
 * setwinsaddr - set the wins address(es)
 * This is primrarly used with the Samba package under UNIX or for pointing
 * the caller to the existing WINS server on a Windows NT platform.
 */
static int setwinsaddr(argv)
char **argv;
{
  u32_t wins;
  struct hostent *hp;

  wins = inet_addr(*argv);
  if (wins == (u32_t)-1) {
    if ((hp = gethostbyname(*argv)) == NULL) {
      option_error("invalid address parameter '%s' for ms-wins option", *argv);
      return 0;
    }
    wins = *(u32_t *)hp->h_addr;
  }

  /* We take the last 2 values given, the 2nd-last as the primary
     and the last as the secondary.  If only one is given it
     becomes both primary and secondary. */
  if (ipcp_allowoptions[0].winsaddr[1] == 0)
    ipcp_allowoptions[0].winsaddr[0] = wins;
  else
    ipcp_allowoptions[0].winsaddr[0] = ipcp_allowoptions[0].winsaddr[1];

  /* always set the secondary address value. */
  ipcp_allowoptions[0].winsaddr[1] = wins;

  return (1);
}

/*
 * setipaddr - Set the IP address
 * If doit is 0, the call is to check whether this option is
 * potentially an IP address specification.
 * Not static so that plugins can call it to set the addresses
 */
int setipaddr(arg, argv, doit)
char *arg;
char **argv;
int doit;
{
  struct hostent *hp;
  char *colon;
  u32_t local, remote;
  ipcp_options *wo = &ipcp_wantoptions[0];
  static int prio_local = 0, prio_remote = 0;

  /*
   * IP address pair separated by ":".
   */
  if ((colon = strchr(arg, ':')) == NULL)
    return 0;
  if (!doit)
    return 1;

  /*
   * If colon first character, then no local addr.
   */
  if (colon != arg && option_priority >= prio_local) {
    *colon = '\0';
    if ((local = inet_addr(arg)) == (u32_t)-1) {
      if ((hp = gethostbyname(arg)) == NULL) {
        option_error("unknown host: %s", arg);
        return 0;
      }
      local = *(u32_t *)hp->h_addr;
    }
    if (bad_ip_adrs(local)) {
      option_error("bad local IP address %s", ip_ntoa(local));
      return 0;
    }
    if (local != 0)
      wo->ouraddr = local;
    *colon = ':';
    prio_local = option_priority;
  }

  /*
   * If colon last character, then no remote addr.
   */
  if (*++colon != '\0' && option_priority >= prio_remote) {
    if ((remote = inet_addr(colon)) == (u32_t)-1) {
      if ((hp = gethostbyname(colon)) == NULL) {
        option_error("unknown host: %s", colon);
        return 0;
      }
      remote = *(u32_t *)hp->h_addr;
      if (remote_name[0] == 0)
        strlcpy(remote_name, colon, sizeof(remote_name));
    }
    if (bad_ip_adrs(remote)) {
      option_error("bad remote IP address %s", ip_ntoa(remote));
      return 0;
    }
    if (remote != 0)
      wo->hisaddr = remote;
    prio_remote = option_priority;
  }

  return 1;
}

static void printipaddr(opt, printer, arg) option_t *opt;
void (*printer)(void *, char *, ...);
void *arg;
{
  ipcp_options *wo = &ipcp_wantoptions[0];

  if (wo->ouraddr != 0)
    printer(arg, "%I", wo->ouraddr);
  printer(arg, ":");
  if (wo->hisaddr != 0)
    printer(arg, "%I", wo->hisaddr);
}

/*
 * setnetmask - set the netmask to be used on the interface.
 */
static int setnetmask(argv)
char **argv;
{
  u32_t mask;
  int n;
  char *p;

  /*
   * Unfortunately, if we use inet_addr, we can't tell whether
   * a result of all 1s is an error or a valid 255.255.255.255.
   */
  p = *argv;
  n = parse_dotted_ip(p, &mask);

  mask = lwip_htonl(mask);

  if (n == 0 || p[n] != 0 || (netmask & ~mask) != 0) {
    option_error("invalid netmask value '%s'", *argv);
    return 0;
  }

  netmask = mask;
  slprintf(netmask_str, sizeof(netmask_str), "%I", mask);

  return (1);
}

int parse_dotted_ip(p, vp)
char *p;
u32_t *vp;
{
  int n;
  u32_t v, b;
  char *endp, *p0 = p;

  v = 0;
  for (n = 3;; --n) {
    b = strtoul(p, &endp, 0);
    if (endp == p)
      return 0;
    if (b > 255) {
      if (n < 3)
        return 0;
      /* accept e.g. 0xffffff00 */
      *vp = b;
      return endp - p0;
    }
    v |= b << (n * 8);
    p = endp;
    if (n == 0)
      break;
    if (*p != '.')
      return 0;
    ++p;
  }
  *vp = v;
  return p - p0;
}
#endif /* PPP_OPTIONS */

/*
 * ipcp_init - Initialize IPCP.
 */
static void ipcp_init(ppp_pcb *pcb) {
  fsm *f = &pcb->ipcp_fsm;

  ipcp_options *wo = &pcb->ipcp_wantoptions;
  ipcp_options *ao = &pcb->ipcp_allowoptions;

  f->pcb = pcb;
  f->protocol = PPP_IPCP;
  f->callbacks = &ipcp_callbacks;
  fsm_init(f);

  /*
   * Some 3G modems use repeated IPCP NAKs as a way of stalling
   * until they can contact a server on the network, so we increase
   * the default number of NAKs we accept before we start treating
   * them as rejects.
   */
  f->maxnakloops = 100;

#if 0  /* Not necessary, everything is cleared in ppp_new() */
    memset(wo, 0, sizeof(*wo));
    memset(ao, 0, sizeof(*ao));
#endif /* 0 */

  wo->neg_addr = wo->old_addrs = 1;
#if VJ_SUPPORT
  wo->neg_vj = 1;
  wo->vj_protocol = IPCP_VJ_COMP;
  wo->maxslotindex = MAX_STATES - 1; /* really max index */
  wo->cflag = 1;
#endif /* VJ_SUPPORT */

#if 0  /* UNUSED */
    /* wanting default route by default */
    wo->default_route = 1;
#endif /* UNUSED */

  ao->neg_addr = ao->old_addrs = 1;
#if VJ_SUPPORT
  /* max slots and slot-id compression are currently hardwired in */
  /* ppp_if.c to 16 and 1, this needs to be changed (among other */
  /* things) gmc */

  ao->neg_vj = 1;
  ao->maxslotindex = MAX_STATES - 1;
  ao->cflag = 1;
#endif /* #if VJ_SUPPORT */

#if 0  /* UNUSED */
    /*
     * XXX These control whether the user may use the proxyarp
     * and defaultroute options.
     */
    ao->proxy_arp = 1;
    ao->default_route = 1;
#endif /* UNUSED */
}

/*
 * ipcp_open - IPCP is allowed to come up.
 */
static void ipcp_open(ppp_pcb *pcb) {
  fsm *f = &pcb->ipcp_fsm;
  fsm_open(f);
  pcb->ipcp_is_open = 1;
}

/*
 * ipcp_close - Take IPCP down.
 */
static void ipcp_close(ppp_pcb *pcb, const char *reason) {
  fsm *f = &pcb->ipcp_fsm;
  fsm_close(f, reason);
}

/*
 * ipcp_lowerup - The lower layer is up.
 */
static void ipcp_lowerup(ppp_pcb *pcb) {
  fsm *f = &pcb->ipcp_fsm;
  fsm_lowerup(f);
}

/*
 * ipcp_lowerdown - The lower layer is down.
 */
static void ipcp_lowerdown(ppp_pcb *pcb) {
  fsm *f = &pcb->ipcp_fsm;
  fsm_lowerdown(f);
}

/*
 * ipcp_input - Input IPCP packet.
 */
static void ipcp_input(ppp_pcb *pcb, u_char *p, int len) {
  fsm *f = &pcb->ipcp_fsm;
  fsm_input(f, p, len);
}

/*
 * ipcp_protrej - A Protocol-Reject was received for IPCP.
 *
 * Pretend the lower layer went down, so we shut up.
 */
static void ipcp_protrej(ppp_pcb *pcb) {
  fsm *f = &pcb->ipcp_fsm;
  fsm_lowerdown(f);
}

/*
 * ipcp_resetci - Reset our CI.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static void ipcp_resetci(fsm *f) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *wo = &pcb->ipcp_wantoptions;
  ipcp_options *go = &pcb->ipcp_gotoptions;
  ipcp_options *ao = &pcb->ipcp_allowoptions;

  wo->req_addr =
      (wo->neg_addr || wo->old_addrs) && (ao->neg_addr || ao->old_addrs);
  if (wo->ouraddr == 0)
    wo->accept_local = 1;
  if (wo->hisaddr == 0)
    wo->accept_remote = 1;
#if LWIP_DNS
  wo->req_dns1 = wo->req_dns2 =
      pcb->settings.usepeerdns; /* Request DNS addresses from the peer */
#endif                          /* LWIP_DNS */
  *go = *wo;
  if (!pcb->ask_for_local)
    go->ouraddr = 0;
#if 0  /* UNUSED */
    if (ip_choose_hook) {
	ip_choose_hook(&wo->hisaddr);
	if (wo->hisaddr) {
	    wo->accept_remote = 0;
	}
    }
#endif /* UNUSED */
  BZERO(&pcb->ipcp_hisoptions, sizeof(ipcp_options));
}

/*
 * ipcp_cilen - Return length of our CI.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static int ipcp_cilen(fsm *f) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *go = &pcb->ipcp_gotoptions;
#if VJ_SUPPORT
  ipcp_options *wo = &pcb->ipcp_wantoptions;
#endif /* VJ_SUPPORT */
  ipcp_options *ho = &pcb->ipcp_hisoptions;

#define LENCIADDRS(neg) (neg ? CILEN_ADDRS : 0)
#if VJ_SUPPORT
#define LENCIVJ(neg, old) (neg ? (old ? CILEN_COMPRESS : CILEN_VJ) : 0)
#endif /* VJ_SUPPORT */
#define LENCIADDR(neg) (neg ? CILEN_ADDR : 0)
#if LWIP_DNS
#define LENCIDNS(neg) LENCIADDR(neg)
#endif /* LWIP_DNS */
#if 0  /* UNUSED - WINS */
#define LENCIWINS(neg) LENCIADDR(neg)
#endif /* UNUSED - WINS */

  /*
   * First see if we want to change our options to the old
   * forms because we have received old forms from the peer.
   */
  if (go->neg_addr && go->old_addrs && !ho->neg_addr && ho->old_addrs)
    go->neg_addr = 0;

#if VJ_SUPPORT
  if (wo->neg_vj && !go->neg_vj && !go->old_vj) {
    /* try an older style of VJ negotiation */
    /* use the old style only if the peer did */
    if (ho->neg_vj && ho->old_vj) {
      go->neg_vj = 1;
      go->old_vj = 1;
      go->vj_protocol = ho->vj_protocol;
    }
  }
#endif /* VJ_SUPPORT */

  return (LENCIADDRS(!go->neg_addr && go->old_addrs) +
#if VJ_SUPPORT
          LENCIVJ(go->neg_vj, go->old_vj) +
#endif /* VJ_SUPPORT */
          LENCIADDR(go->neg_addr) +
#if LWIP_DNS
          LENCIDNS(go->req_dns1) + LENCIDNS(go->req_dns2) +
#endif /* LWIP_DNS */
#if 0  /* UNUSED - WINS */
	    LENCIWINS(go->winsaddr[0]) +
	    LENCIWINS(go->winsaddr[1]) +
#endif /* UNUSED - WINS */
          0);
}

/*
 * ipcp_addci - Add our desired CIs to a packet.
 * Called by fsm_sconfreq, Send Configure Request.
 */
static void ipcp_addci(fsm *f, u_char *ucp, int *lenp) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *go = &pcb->ipcp_gotoptions;
  int len = *lenp;

#define ADDCIADDRS(opt, neg, val1, val2)                                       \
  if (neg) {                                                                   \
    if (len >= CILEN_ADDRS) {                                                  \
      u32_t l;                                                                 \
      PUTCHAR(opt, ucp);                                                       \
      PUTCHAR(CILEN_ADDRS, ucp);                                               \
      l = lwip_ntohl(val1);                                                    \
      PUTLONG(l, ucp);                                                         \
      l = lwip_ntohl(val2);                                                    \
      PUTLONG(l, ucp);                                                         \
      len -= CILEN_ADDRS;                                                      \
    } else                                                                     \
      go->old_addrs = 0;                                                       \
  }

#if VJ_SUPPORT
#define ADDCIVJ(opt, neg, val, old, maxslotindex, cflag)                       \
  if (neg) {                                                                   \
    int vjlen = old ? CILEN_COMPRESS : CILEN_VJ;                               \
    if (len >= vjlen) {                                                        \
      PUTCHAR(opt, ucp);                                                       \
      PUTCHAR(vjlen, ucp);                                                     \
      PUTSHORT(val, ucp);                                                      \
      if (!old) {                                                              \
        PUTCHAR(maxslotindex, ucp);                                            \
        PUTCHAR(cflag, ucp);                                                   \
      }                                                                        \
      len -= vjlen;                                                            \
    } else                                                                     \
      neg = 0;                                                                 \
  }
#endif /* VJ_SUPPORT */

#define ADDCIADDR(opt, neg, val)                                               \
  if (neg) {                                                                   \
    if (len >= CILEN_ADDR) {                                                   \
      u32_t l;                                                                 \
      PUTCHAR(opt, ucp);                                                       \
      PUTCHAR(CILEN_ADDR, ucp);                                                \
      l = lwip_ntohl(val);                                                     \
      PUTLONG(l, ucp);                                                         \
      len -= CILEN_ADDR;                                                       \
    } else                                                                     \
      neg = 0;                                                                 \
  }

#if LWIP_DNS
#define ADDCIDNS(opt, neg, addr)                                               \
  if (neg) {                                                                   \
    if (len >= CILEN_ADDR) {                                                   \
      u32_t l;                                                                 \
      PUTCHAR(opt, ucp);                                                       \
      PUTCHAR(CILEN_ADDR, ucp);                                                \
      l = lwip_ntohl(addr);                                                    \
      PUTLONG(l, ucp);                                                         \
      len -= CILEN_ADDR;                                                       \
    } else                                                                     \
      neg = 0;                                                                 \
  }
#endif /* LWIP_DNS */

#if 0 /* UNUSED - WINS */
#define ADDCIWINS(opt, addr)                                                   \
  if (addr) {                                                                  \
    if (len >= CILEN_ADDR) {                                                   \
      u32_t l;                                                                 \
      PUTCHAR(opt, ucp);                                                       \
      PUTCHAR(CILEN_ADDR, ucp);                                                \
      l = lwip_ntohl(addr);                                                    \
      PUTLONG(l, ucp);                                                         \
      len -= CILEN_ADDR;                                                       \
    } else                                                                     \
      addr = 0;                                                                \
  }
#endif /* UNUSED - WINS */

  ADDCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs, go->ouraddr,
             go->hisaddr);

#if VJ_SUPPORT
  ADDCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
          go->maxslotindex, go->cflag);
#endif /* VJ_SUPPORT */

  ADDCIADDR(CI_ADDR, go->neg_addr, go->ouraddr);

#if LWIP_DNS
  ADDCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

  ADDCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);
#endif /* LWIP_DNS */

#if 0  /* UNUSED - WINS */
    ADDCIWINS(CI_MS_WINS1, go->winsaddr[0]);

    ADDCIWINS(CI_MS_WINS2, go->winsaddr[1]);
#endif /* UNUSED - WINS */

  *lenp -= len;
}

/*
 * ipcp_ackci - Ack our CIs.
 * Called by fsm_rconfack, Receive Configure ACK.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int ipcp_ackci(fsm *f, u_char *p, int len) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *go = &pcb->ipcp_gotoptions;
  u_short cilen, citype;
  u32_t cilong;
#if VJ_SUPPORT
  u_short cishort;
  u_char cimaxslotindex, cicflag;
#endif /* VJ_SUPPORT */

  /*
   * CIs must be in exactly the same order that we sent...
   * Check packet length and CI length at each step.
   * If we find any deviations, then this packet is bad.
   */

#define ACKCIADDRS(opt, neg, val1, val2)                                       \
  if (neg) {                                                                   \
    u32_t l;                                                                   \
    if ((len -= CILEN_ADDRS) < 0)                                              \
      goto bad;                                                                \
    GETCHAR(citype, p);                                                        \
    GETCHAR(cilen, p);                                                         \
    if (cilen != CILEN_ADDRS || citype != opt)                                 \
      goto bad;                                                                \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    if (val1 != cilong)                                                        \
      goto bad;                                                                \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    if (val2 != cilong)                                                        \
      goto bad;                                                                \
  }

#if VJ_SUPPORT
#define ACKCIVJ(opt, neg, val, old, maxslotindex, cflag)                       \
  if (neg) {                                                                   \
    int vjlen = old ? CILEN_COMPRESS : CILEN_VJ;                               \
    if ((len -= vjlen) < 0)                                                    \
      goto bad;                                                                \
    GETCHAR(citype, p);                                                        \
    GETCHAR(cilen, p);                                                         \
    if (cilen != vjlen || citype != opt)                                       \
      goto bad;                                                                \
    GETSHORT(cishort, p);                                                      \
    if (cishort != val)                                                        \
      goto bad;                                                                \
    if (!old) {                                                                \
      GETCHAR(cimaxslotindex, p);                                              \
      if (cimaxslotindex != maxslotindex)                                      \
        goto bad;                                                              \
      GETCHAR(cicflag, p);                                                     \
      if (cicflag != cflag)                                                    \
        goto bad;                                                              \
    }                                                                          \
  }
#endif /* VJ_SUPPORT */

#define ACKCIADDR(opt, neg, val)                                               \
  if (neg) {                                                                   \
    u32_t l;                                                                   \
    if ((len -= CILEN_ADDR) < 0)                                               \
      goto bad;                                                                \
    GETCHAR(citype, p);                                                        \
    GETCHAR(cilen, p);                                                         \
    if (cilen != CILEN_ADDR || citype != opt)                                  \
      goto bad;                                                                \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    if (val != cilong)                                                         \
      goto bad;                                                                \
  }

#if LWIP_DNS
#define ACKCIDNS(opt, neg, addr)                                               \
  if (neg) {                                                                   \
    u32_t l;                                                                   \
    if ((len -= CILEN_ADDR) < 0)                                               \
      goto bad;                                                                \
    GETCHAR(citype, p);                                                        \
    GETCHAR(cilen, p);                                                         \
    if (cilen != CILEN_ADDR || citype != opt)                                  \
      goto bad;                                                                \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    if (addr != cilong)                                                        \
      goto bad;                                                                \
  }
#endif /* LWIP_DNS */

#if 0 /* UNUSED - WINS */
#define ACKCIWINS(opt, addr)                                                   \
  if (addr) {                                                                  \
    u32_t l;                                                                   \
    if ((len -= CILEN_ADDR) < 0)                                               \
      goto bad;                                                                \
    GETCHAR(citype, p);                                                        \
    GETCHAR(cilen, p);                                                         \
    if (cilen != CILEN_ADDR || citype != opt)                                  \
      goto bad;                                                                \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    if (addr != cilong)                                                        \
      goto bad;                                                                \
  }
#endif /* UNUSED - WINS */

  ACKCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs, go->ouraddr,
             go->hisaddr);

#if VJ_SUPPORT
  ACKCIVJ(CI_COMPRESSTYPE, go->neg_vj, go->vj_protocol, go->old_vj,
          go->maxslotindex, go->cflag);
#endif /* VJ_SUPPORT */

  ACKCIADDR(CI_ADDR, go->neg_addr, go->ouraddr);

#if LWIP_DNS
  ACKCIDNS(CI_MS_DNS1, go->req_dns1, go->dnsaddr[0]);

  ACKCIDNS(CI_MS_DNS2, go->req_dns2, go->dnsaddr[1]);
#endif /* LWIP_DNS */

#if 0  /* UNUSED - WINS */
    ACKCIWINS(CI_MS_WINS1, go->winsaddr[0]);

    ACKCIWINS(CI_MS_WINS2, go->winsaddr[1]);
#endif /* UNUSED - WINS */

  /*
   * If there are any remaining CIs, then this packet is bad.
   */
  if (len != 0)
    goto bad;
  return (1);

bad:
  IPCPDEBUG(("ipcp_ackci: received bad Ack!"));
  return (0);
}

/*
 * ipcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if IPCP is in the OPENED state.
 * Callback from fsm_rconfnakrej - Receive Configure-Nak or Configure-Reject.
 *
 * Returns:
 *	0 - Nak was bad.
 *	1 - Nak was good.
 */
static int ipcp_nakci(fsm *f, u_char *p, int len, int treat_as_reject) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *go = &pcb->ipcp_gotoptions;
  u_char citype, cilen, *next;
#if VJ_SUPPORT
  u_char cimaxslotindex, cicflag;
  u_short cishort;
#endif /* VJ_SUPPORT */
  u32_t ciaddr1, ciaddr2, l;
#if LWIP_DNS
  u32_t cidnsaddr;
#endif               /* LWIP_DNS */
  ipcp_options no;   /* options we've seen Naks for */
  ipcp_options try_; /* options to request next time */

  BZERO(&no, sizeof(no));
  try_ = *go;

  /*
   * Any Nak'd CIs must be in exactly the same order that we sent.
   * Check packet length and CI length at each step.
   * If we find any deviations, then this packet is bad.
   */
#define NAKCIADDRS(opt, neg, code)                                             \
  if ((neg) && (cilen = p[1]) == CILEN_ADDRS && len >= cilen && p[0] == opt) { \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    ciaddr1 = lwip_htonl(l);                                                   \
    GETLONG(l, p);                                                             \
    ciaddr2 = lwip_htonl(l);                                                   \
    no.old_addrs = 1;                                                          \
    code                                                                       \
  }

#if VJ_SUPPORT
#define NAKCIVJ(opt, neg, code)                                                \
  if (go->neg && ((cilen = p[1]) == CILEN_COMPRESS || cilen == CILEN_VJ) &&    \
      len >= cilen && p[0] == opt) {                                           \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETSHORT(cishort, p);                                                      \
    no.neg = 1;                                                                \
    code                                                                       \
  }
#endif /* VJ_SUPPORT */

#define NAKCIADDR(opt, neg, code)                                              \
  if (go->neg && (cilen = p[1]) == CILEN_ADDR && len >= cilen &&               \
      p[0] == opt) {                                                           \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    ciaddr1 = lwip_htonl(l);                                                   \
    no.neg = 1;                                                                \
    code                                                                       \
  }

#if LWIP_DNS
#define NAKCIDNS(opt, neg, code)                                               \
  if (go->neg && ((cilen = p[1]) == CILEN_ADDR) && len >= cilen &&             \
      p[0] == opt) {                                                           \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    cidnsaddr = lwip_htonl(l);                                                 \
    no.neg = 1;                                                                \
    code                                                                       \
  }
#endif /* LWIP_DNS */

  /*
   * Accept the peer's idea of {our,his} address, if different
   * from our idea, only if the accept_{local,remote} flag is set.
   */
  NAKCIADDRS(
      CI_ADDRS, !go->neg_addr && go->old_addrs,
      if (treat_as_reject) { try_.old_addrs = 0; } else {
        if (go->accept_local && ciaddr1) {
          /* take his idea of our address */
          try_.ouraddr = ciaddr1;
        }
        if (go->accept_remote && ciaddr2) {
          /* take his idea of his address */
          try_.hisaddr = ciaddr2;
        }
      });

#if VJ_SUPPORT
  /*
   * Accept the peer's value of maxslotindex provided that it
   * is less than what we asked for.  Turn off slot-ID compression
   * if the peer wants.  Send old-style compress-type option if
   * the peer wants.
   */
  NAKCIVJ(
      CI_COMPRESSTYPE, neg_vj,
      if (treat_as_reject) { try_.neg_vj = 0; } else if (cilen == CILEN_VJ) {
        GETCHAR(cimaxslotindex, p);
        GETCHAR(cicflag, p);
        if (cishort == IPCP_VJ_COMP) {
          try_.old_vj = 0;
          if (cimaxslotindex < go->maxslotindex)
            try_.maxslotindex = cimaxslotindex;
          if (!cicflag)
            try_.cflag = 0;
        } else {
          try_.neg_vj = 0;
        }
      } else {
        if (cishort == IPCP_VJ_COMP || cishort == IPCP_VJ_COMP_OLD) {
          try_.old_vj = 1;
          try_.vj_protocol = cishort;
        } else {
          try_.neg_vj = 0;
        }
      });
#endif /* VJ_SUPPORT */

  NAKCIADDR(
      CI_ADDR, neg_addr,
      if (treat_as_reject) {
        try_.neg_addr = 0;
        try_.old_addrs = 0;
      } else if (go->accept_local && ciaddr1) {
        /* take his idea of our address */
        try_.ouraddr = ciaddr1;
      });

#if LWIP_DNS
  NAKCIDNS(
      CI_MS_DNS1, req_dns1, if (treat_as_reject) { try_.req_dns1 = 0; } else {
        try_.dnsaddr[0] = cidnsaddr;
      });

  NAKCIDNS(
      CI_MS_DNS2, req_dns2, if (treat_as_reject) { try_.req_dns2 = 0; } else {
        try_.dnsaddr[1] = cidnsaddr;
      });
#endif /* #if LWIP_DNS */

  /*
   * There may be remaining CIs, if the peer is requesting negotiation
   * on an option that we didn't include in our request packet.
   * If they want to negotiate about IP addresses, we comply.
   * If they want us to ask for compression, we refuse.
   * If they want us to ask for ms-dns, we do that, since some
   * peers get huffy if we don't.
   */
  while (len >= CILEN_VOID) {
    GETCHAR(citype, p);
    GETCHAR(cilen, p);
    if (cilen < CILEN_VOID || (len -= cilen) < 0)
      goto bad;
    next = p + cilen - 2;

    switch (citype) {
#if VJ_SUPPORT
    case CI_COMPRESSTYPE:
      if (go->neg_vj || no.neg_vj ||
          (cilen != CILEN_VJ && cilen != CILEN_COMPRESS))
        goto bad;
      no.neg_vj = 1;
      break;
#endif /* VJ_SUPPORT */
    case CI_ADDRS:
      if ((!go->neg_addr && go->old_addrs) || no.old_addrs ||
          cilen != CILEN_ADDRS)
        goto bad;
      try_.neg_addr = 0;
      GETLONG(l, p);
      ciaddr1 = lwip_htonl(l);
      if (ciaddr1 && go->accept_local)
        try_.ouraddr = ciaddr1;
      GETLONG(l, p);
      ciaddr2 = lwip_htonl(l);
      if (ciaddr2 && go->accept_remote)
        try_.hisaddr = ciaddr2;
      no.old_addrs = 1;
      break;
    case CI_ADDR:
      if (go->neg_addr || no.neg_addr || cilen != CILEN_ADDR)
        goto bad;
      try_.old_addrs = 0;
      GETLONG(l, p);
      ciaddr1 = lwip_htonl(l);
      if (ciaddr1 && go->accept_local)
        try_.ouraddr = ciaddr1;
      if (try_.ouraddr != 0)
        try_.neg_addr = 1;
      no.neg_addr = 1;
      break;
#if LWIP_DNS
    case CI_MS_DNS1:
      if (go->req_dns1 || no.req_dns1 || cilen != CILEN_ADDR)
        goto bad;
      GETLONG(l, p);
      try_.dnsaddr[0] = lwip_htonl(l);
      try_.req_dns1 = 1;
      no.req_dns1 = 1;
      break;
    case CI_MS_DNS2:
      if (go->req_dns2 || no.req_dns2 || cilen != CILEN_ADDR)
        goto bad;
      GETLONG(l, p);
      try_.dnsaddr[1] = lwip_htonl(l);
      try_.req_dns2 = 1;
      no.req_dns2 = 1;
      break;
#endif /* LWIP_DNS */
#if 0  /* UNUSED - WINS */
	case CI_MS_WINS1:
	case CI_MS_WINS2:
	    if (cilen != CILEN_ADDR)
		goto bad;
	    GETLONG(l, p);
	    ciaddr1 = lwip_htonl(l);
	    if (ciaddr1)
		try_.winsaddr[citype == CI_MS_WINS2] = ciaddr1;
	    break;
#endif /* UNUSED - WINS */
    default:
      break;
    }
    p = next;
  }

  /*
   * OK, the Nak is good.  Now we can update state.
   * If there are any remaining options, we ignore them.
   */
  if (f->state != PPP_FSM_OPENED)
    *go = try_;

  return 1;

bad:
  IPCPDEBUG(("ipcp_nakci: received bad Nak!"));
  return 0;
}

/*
 * ipcp_rejci - Reject some of our CIs.
 * Callback from fsm_rconfnakrej.
 */
static int ipcp_rejci(fsm *f, u_char *p, int len) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *go = &pcb->ipcp_gotoptions;
  u_char cilen;
#if VJ_SUPPORT
  u_char cimaxslotindex, ciflag;
  u_short cishort;
#endif /* VJ_SUPPORT */
  u32_t cilong;
  ipcp_options try_; /* options to request next time */

  try_ = *go;
  /*
   * Any Rejected CIs must be in exactly the same order that we sent.
   * Check packet length and CI length at each step.
   * If we find any deviations, then this packet is bad.
   */
#define REJCIADDRS(opt, neg, val1, val2)                                       \
  if ((neg) && (cilen = p[1]) == CILEN_ADDRS && len >= cilen && p[0] == opt) { \
    u32_t l;                                                                   \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    /* Check rejected value. */                                                \
    if (cilong != val1)                                                        \
      goto bad;                                                                \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    /* Check rejected value. */                                                \
    if (cilong != val2)                                                        \
      goto bad;                                                                \
    try_.old_addrs = 0;                                                        \
  }

#if VJ_SUPPORT
#define REJCIVJ(opt, neg, val, old, maxslot, cflag)                            \
  if (go->neg && p[1] == (old ? CILEN_COMPRESS : CILEN_VJ) && len >= p[1] &&   \
      p[0] == opt) {                                                           \
    len -= p[1];                                                               \
    INCPTR(2, p);                                                              \
    GETSHORT(cishort, p);                                                      \
    /* Check rejected value. */                                                \
    if (cishort != val)                                                        \
      goto bad;                                                                \
    if (!old) {                                                                \
      GETCHAR(cimaxslotindex, p);                                              \
      if (cimaxslotindex != maxslot)                                           \
        goto bad;                                                              \
      GETCHAR(ciflag, p);                                                      \
      if (ciflag != cflag)                                                     \
        goto bad;                                                              \
    }                                                                          \
    try_.neg = 0;                                                              \
  }
#endif /* VJ_SUPPORT */

#define REJCIADDR(opt, neg, val)                                               \
  if (go->neg && (cilen = p[1]) == CILEN_ADDR && len >= cilen &&               \
      p[0] == opt) {                                                           \
    u32_t l;                                                                   \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    /* Check rejected value. */                                                \
    if (cilong != val)                                                         \
      goto bad;                                                                \
    try_.neg = 0;                                                              \
  }

#if LWIP_DNS
#define REJCIDNS(opt, neg, dnsaddr)                                            \
  if (go->neg && ((cilen = p[1]) == CILEN_ADDR) && len >= cilen &&             \
      p[0] == opt) {                                                           \
    u32_t l;                                                                   \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    /* Check rejected value. */                                                \
    if (cilong != dnsaddr)                                                     \
      goto bad;                                                                \
    try_.neg = 0;                                                              \
  }
#endif /* LWIP_DNS */

#if 0 /* UNUSED - WINS */
#define REJCIWINS(opt, addr)                                                   \
  if (addr && ((cilen = p[1]) == CILEN_ADDR) && len >= cilen && p[0] == opt) { \
    u32_t l;                                                                   \
    len -= cilen;                                                              \
    INCPTR(2, p);                                                              \
    GETLONG(l, p);                                                             \
    cilong = lwip_htonl(l);                                                    \
    /* Check rejected value. */                                                \
    if (cilong != addr)                                                        \
      goto bad;                                                                \
    try_.winsaddr[opt == CI_MS_WINS2] = 0;                                     \
  }
#endif /* UNUSED - WINS */

  REJCIADDRS(CI_ADDRS, !go->neg_addr && go->old_addrs, go->ouraddr,
             go->hisaddr);

#if VJ_SUPPORT
  REJCIVJ(CI_COMPRESSTYPE, neg_vj, go->vj_protocol, go->old_vj,
          go->maxslotindex, go->cflag);
#endif /* VJ_SUPPORT */

  REJCIADDR(CI_ADDR, neg_addr, go->ouraddr);

#if LWIP_DNS
  REJCIDNS(CI_MS_DNS1, req_dns1, go->dnsaddr[0]);

  REJCIDNS(CI_MS_DNS2, req_dns2, go->dnsaddr[1]);
#endif /* LWIP_DNS */

#if 0  /* UNUSED - WINS */
    REJCIWINS(CI_MS_WINS1, go->winsaddr[0]);

    REJCIWINS(CI_MS_WINS2, go->winsaddr[1]);
#endif /* UNUSED - WINS */

  /*
   * If there are any remaining CIs, then this packet is bad.
   */
  if (len != 0)
    goto bad;
  /*
   * Now we can update state.
   */
  if (f->state != PPP_FSM_OPENED)
    *go = try_;
  return 1;

bad:
  IPCPDEBUG(("ipcp_rejci: received bad Reject!"));
  return 0;
}

/*
 * ipcp_reqci - Check the peer's requested CIs and send appropriate response.
 * Callback from fsm_rconfreq, Receive Configure Request
 *
 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
 * appropriately.  If reject_if_disagree is non-zero, doesn't return
 * CONFNAK; returns CONFREJ if it can't return CONFACK.
 *
 * inp = Requested CIs
 * len = Length of requested CIs
 */
static int ipcp_reqci(fsm *f, u_char *inp, int *len, int reject_if_disagree) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *wo = &pcb->ipcp_wantoptions;
  ipcp_options *ho = &pcb->ipcp_hisoptions;
  ipcp_options *ao = &pcb->ipcp_allowoptions;
  u_char *cip, *next;    /* Pointer to current and next CIs */
  u_short cilen, citype; /* Parsed len, type */
#if VJ_SUPPORT
  u_short cishort;            /* Parsed short value */
#endif                        /* VJ_SUPPORT */
  u32_t tl, ciaddr1, ciaddr2; /* Parsed address values */
  int rc = CONFACK;           /* Final packet return code */
  int orc;                    /* Individual option return code */
  u_char *p;                  /* Pointer to next char to parse */
  u_char *ucp = inp;          /* Pointer to current output char */
  int l = *len;               /* Length left */
#if VJ_SUPPORT
  u_char maxslotindex, cflag;
#endif /* VJ_SUPPORT */
#if LWIP_DNS
  int d;
#endif /* LWIP_DNS */

  /*
   * Reset all his options.
   */
  BZERO(ho, sizeof(*ho));

  /*
   * Process all his options.
   */
  next = inp;
  while (l) {
    orc = CONFACK;  /* Assume success */
    cip = p = next; /* Remember beginning of CI */
    if (l < 2 ||    /* Not enough data for CI header or */
        p[1] < 2 || /*  CI length too small or */
        p[1] > l) { /*  CI length too big? */
      IPCPDEBUG(("ipcp_reqci: bad CI length!"));
      orc = CONFREJ; /* Reject bad CI */
      cilen = l;     /* Reject till end of packet */
      l = 0;         /* Don't loop again */
      goto endswitch;
    }
    GETCHAR(citype, p); /* Parse CI type */
    GETCHAR(cilen, p);  /* Parse CI length */
    l -= cilen;         /* Adjust remaining length */
    next += cilen;      /* Step to next CI */

    switch (citype) { /* Check CI type */
    case CI_ADDRS:
      if (!ao->old_addrs || ho->neg_addr ||
          cilen != CILEN_ADDRS) { /* Check CI length */
        orc = CONFREJ;            /* Reject CI */
        break;
      }

      /*
       * If he has no address, or if we both have his address but
       * disagree about it, then NAK it with our idea.
       * In particular, if we don't know his address, but he does,
       * then accept it.
       */
      GETLONG(tl, p); /* Parse source address (his) */
      ciaddr1 = lwip_htonl(tl);
      if (ciaddr1 != wo->hisaddr && (ciaddr1 == 0 || !wo->accept_remote)) {
        orc = CONFNAK;
        if (!reject_if_disagree) {
          DECPTR(sizeof(u32_t), p);
          tl = lwip_ntohl(wo->hisaddr);
          PUTLONG(tl, p);
        }
      } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
        /*
         * If neither we nor he knows his address, reject the option.
         */
        orc = CONFREJ;
        wo->req_addr = 0; /* don't NAK with 0.0.0.0 later */
        break;
      }

      /*
       * If he doesn't know our address, or if we both have our address
       * but disagree about it, then NAK it with our idea.
       */
      GETLONG(tl, p); /* Parse destination address (ours) */
      ciaddr2 = lwip_htonl(tl);
      if (ciaddr2 != wo->ouraddr) {
        if (ciaddr2 == 0 || !wo->accept_local) {
          orc = CONFNAK;
          if (!reject_if_disagree) {
            DECPTR(sizeof(u32_t), p);
            tl = lwip_ntohl(wo->ouraddr);
            PUTLONG(tl, p);
          }
        } else {
          wo->ouraddr = ciaddr2; /* accept peer's idea */
        }
      }

      ho->old_addrs = 1;
      ho->hisaddr = ciaddr1;
      ho->ouraddr = ciaddr2;
      break;

    case CI_ADDR:
      if (!ao->neg_addr || ho->old_addrs ||
          cilen != CILEN_ADDR) { /* Check CI length */
        orc = CONFREJ;           /* Reject CI */
        break;
      }

      /*
       * If he has no address, or if we both have his address but
       * disagree about it, then NAK it with our idea.
       * In particular, if we don't know his address, but he does,
       * then accept it.
       */
      GETLONG(tl, p); /* Parse source address (his) */
      ciaddr1 = lwip_htonl(tl);
      if (ciaddr1 != wo->hisaddr && (ciaddr1 == 0 || !wo->accept_remote)) {
        orc = CONFNAK;
        if (!reject_if_disagree) {
          DECPTR(sizeof(u32_t), p);
          tl = lwip_ntohl(wo->hisaddr);
          PUTLONG(tl, p);
        }
      } else if (ciaddr1 == 0 && wo->hisaddr == 0) {
        /*
         * Don't ACK an address of 0.0.0.0 - reject it instead.
         */
        orc = CONFREJ;
        wo->req_addr = 0; /* don't NAK with 0.0.0.0 later */
        break;
      }

      ho->neg_addr = 1;
      ho->hisaddr = ciaddr1;
      break;

#if LWIP_DNS
    case CI_MS_DNS1:
    case CI_MS_DNS2:
      /* Microsoft primary or secondary DNS request */
      d = citype == CI_MS_DNS2;

      /* If we do not have a DNS address then we cannot send it */
      if (ao->dnsaddr[d] == 0 || cilen != CILEN_ADDR) { /* Check CI length */
        orc = CONFREJ;                                  /* Reject CI */
        break;
      }
      GETLONG(tl, p);
      if (lwip_htonl(tl) != ao->dnsaddr[d]) {
        DECPTR(sizeof(u32_t), p);
        tl = lwip_ntohl(ao->dnsaddr[d]);
        PUTLONG(tl, p);
        orc = CONFNAK;
      }
      break;
#endif /* LWIP_DNS */

#if 0  /* UNUSED - WINS */
	case CI_MS_WINS1:
	case CI_MS_WINS2:
	    /* Microsoft primary or secondary WINS request */
	    d = citype == CI_MS_WINS2;

	    /* If we do not have a DNS address then we cannot send it */
	    if (ao->winsaddr[d] == 0 ||
		cilen != CILEN_ADDR) {	/* Check CI length */
		orc = CONFREJ;		/* Reject CI */
		break;
	    }
	    GETLONG(tl, p);
	    if (lwip_htonl(tl) != ao->winsaddr[d]) {
                DECPTR(sizeof(u32_t), p);
		tl = lwip_ntohl(ao->winsaddr[d]);
		PUTLONG(tl, p);
		orc = CONFNAK;
            }
            break;
#endif /* UNUSED - WINS */

#if VJ_SUPPORT
    case CI_COMPRESSTYPE:
      if (!ao->neg_vj || (cilen != CILEN_VJ && cilen != CILEN_COMPRESS)) {
        orc = CONFREJ;
        break;
      }
      GETSHORT(cishort, p);

      if (!(cishort == IPCP_VJ_COMP ||
            (cishort == IPCP_VJ_COMP_OLD && cilen == CILEN_COMPRESS))) {
        orc = CONFREJ;
        break;
      }

      ho->neg_vj = 1;
      ho->vj_protocol = cishort;
      if (cilen == CILEN_VJ) {
        GETCHAR(maxslotindex, p);
        if (maxslotindex > ao->maxslotindex) {
          orc = CONFNAK;
          if (!reject_if_disagree) {
            DECPTR(1, p);
            PUTCHAR(ao->maxslotindex, p);
          }
        }
        GETCHAR(cflag, p);
        if (cflag && !ao->cflag) {
          orc = CONFNAK;
          if (!reject_if_disagree) {
            DECPTR(1, p);
            PUTCHAR(wo->cflag, p);
          }
        }
        ho->maxslotindex = maxslotindex;
        ho->cflag = cflag;
      } else {
        ho->old_vj = 1;
        ho->maxslotindex = MAX_STATES - 1;
        ho->cflag = 1;
      }
      break;
#endif /* VJ_SUPPORT */

    default:
      orc = CONFREJ;
      break;
    }
  endswitch:
    if (orc == CONFACK && /* Good CI */
        rc != CONFACK)    /*  but prior CI wasn't? */
      continue;           /* Don't send this one */

    if (orc == CONFNAK) {     /* Nak this CI? */
      if (reject_if_disagree) /* Getting fed up with sending NAKs? */
        orc = CONFREJ;        /* Get tough if so */
      else {
        if (rc == CONFREJ)   /* Rejecting prior CI? */
          continue;          /* Don't send this one */
        if (rc == CONFACK) { /* Ack'd all prior CIs? */
          rc = CONFNAK;      /* Not anymore... */
          ucp = inp;         /* Backup */
        }
      }
    }

    if (orc == CONFREJ && /* Reject this CI */
        rc != CONFREJ) {  /*  but no prior ones? */
      rc = CONFREJ;
      ucp = inp; /* Backup */
    }

    /* Need to move CI? */
    if (ucp != cip)
      MEMCPY(ucp, cip, cilen); /* Move it */

    /* Update output pointer */
    INCPTR(cilen, ucp);
  }

  /*
   * If we aren't rejecting this packet, and we want to negotiate
   * their address, and they didn't send their address, then we
   * send a NAK with a CI_ADDR option appended.  We assume the
   * input buffer is long enough that we can append the extra
   * option safely.
   */
  if (rc != CONFREJ && !ho->neg_addr && !ho->old_addrs && wo->req_addr &&
      !reject_if_disagree && !pcb->settings.noremoteip) {
    if (rc == CONFACK) {
      rc = CONFNAK;
      ucp = inp;        /* reset pointer */
      wo->req_addr = 0; /* don't ask again */
    }
    PUTCHAR(CI_ADDR, ucp);
    PUTCHAR(CILEN_ADDR, ucp);
    tl = lwip_ntohl(wo->hisaddr);
    PUTLONG(tl, ucp);
  }

  *len = ucp - inp; /* Compute output length */
  IPCPDEBUG(("ipcp: returning Configure-%s", CODENAME(rc)));
  return (rc); /* Return final code */
}

#if 0  /* UNUSED */
/*
 * ip_check_options - check that any IP-related options are OK,
 * and assign appropriate defaults.
 */
static void
ip_check_options()
{
    struct hostent *hp;
    u32_t local;
    ipcp_options *wo = &ipcp_wantoptions[0];

    /*
     * Default our local IP address based on our hostname.
     * If local IP address already given, don't bother.
     */
    if (wo->ouraddr == 0 && !disable_defaultip) {
	/*
	 * Look up our hostname (possibly with domain name appended)
	 * and take the first IP address as our local IP address.
	 * If there isn't an IP address for our hostname, too bad.
	 */
	wo->accept_local = 1;	/* don't insist on this default value */
	if ((hp = gethostbyname(hostname)) != NULL) {
	    local = *(u32_t *)hp->h_addr;
	    if (local != 0 && !bad_ip_adrs(local))
		wo->ouraddr = local;
	}
    }
    ask_for_local = wo->ouraddr != 0 || !disable_defaultip;
}
#endif /* UNUSED */

#if DEMAND_SUPPORT
/*
 * ip_demand_conf - configure the interface as though
 * IPCP were up, for use with dial-on-demand.
 */
static int ip_demand_conf(u)
int u;
{
  ppp_pcb *pcb = &ppp_pcb_list[u];
  ipcp_options *wo = &ipcp_wantoptions[u];

  if (wo->hisaddr == 0 && !pcb->settings.noremoteip) {
    /* make up an arbitrary address for the peer */
    wo->hisaddr = lwip_htonl(0x0a707070 + ifunit);
    wo->accept_remote = 1;
  }
  if (wo->ouraddr == 0) {
    /* make up an arbitrary address for us */
    wo->ouraddr = lwip_htonl(0x0a404040 + ifunit);
    wo->accept_local = 1;
    ask_for_local = 0; /* don't tell the peer this address */
  }
  if (!sifaddr(pcb, wo->ouraddr, wo->hisaddr, get_mask(wo->ouraddr)))
    return 0;
  if (!sifup(pcb))
    return 0;
  if (!sifnpmode(pcb, PPP_IP, NPMODE_QUEUE))
    return 0;
#if 0  /* UNUSED */
    if (wo->default_route)
	if (sifdefaultroute(pcb, wo->ouraddr, wo->hisaddr,
		wo->replace_default_route))
	    default_route_set[u] = 1;
#endif /* UNUSED */
#if 0  /* UNUSED - PROXY ARP */
    if (wo->proxy_arp)
	if (sifproxyarp(pcb, wo->hisaddr))
	    proxy_arp_set[u] = 1;
#endif /* UNUSED - PROXY ARP */

  ppp_notice(("local  IP address %I", wo->ouraddr));
  if (wo->hisaddr)
    ppp_notice(("remote IP address %I", wo->hisaddr));

  return 1;
}
#endif /* DEMAND_SUPPORT */

/*
 * ipcp_up - IPCP has come UP.
 *
 * Configure the IP network interface appropriately and bring it up.
 */
static void ipcp_up(fsm *f) {
  ppp_pcb *pcb = f->pcb;
  u32_t mask;
  ipcp_options *ho = &pcb->ipcp_hisoptions;
  ipcp_options *go = &pcb->ipcp_gotoptions;
  ipcp_options *wo = &pcb->ipcp_wantoptions;

  IPCPDEBUG(("ipcp: up"));

  /*
   * We must have a non-zero IP address for both ends of the link.
   */
  if (!ho->neg_addr && !ho->old_addrs)
    ho->hisaddr = wo->hisaddr;

  if (!(go->neg_addr || go->old_addrs) && (wo->neg_addr || wo->old_addrs) &&
      wo->ouraddr != 0) {
    ppp_error(("Peer refused to agree to our IP address"));
    ipcp_close(f->pcb, "Refused our IP address");
    return;
  }
  if (go->ouraddr == 0) {
    ppp_error(("Could not determine local IP address"));
    ipcp_close(f->pcb, "Could not determine local IP address");
    return;
  }
  if (ho->hisaddr == 0 && !pcb->settings.noremoteip) {
    ho->hisaddr = lwip_htonl(0x0a404040);
    ppp_warn(("Could not determine remote IP address: defaulting to %I",
              ho->hisaddr));
  }
#if 0  /* UNUSED */
    script_setenv("IPLOCAL", ip_ntoa(go->ouraddr), 0);
    if (ho->hisaddr != 0)
	script_setenv("IPREMOTE", ip_ntoa(ho->hisaddr), 1);
#endif /* UNUSED */

#if LWIP_DNS
  if (!go->req_dns1)
    go->dnsaddr[0] = 0;
  if (!go->req_dns2)
    go->dnsaddr[1] = 0;
#if 0  /* UNUSED */
    if (go->dnsaddr[0])
	script_setenv("DNS1", ip_ntoa(go->dnsaddr[0]), 0);
    if (go->dnsaddr[1])
	script_setenv("DNS2", ip_ntoa(go->dnsaddr[1]), 0);
#endif /* UNUSED */
  if (pcb->settings.usepeerdns && (go->dnsaddr[0] || go->dnsaddr[1])) {
    sdns(pcb, go->dnsaddr[0], go->dnsaddr[1]);
#if 0  /* UNUSED */
	script_setenv("USEPEERDNS", "1", 0);
	create_resolv(go->dnsaddr[0], go->dnsaddr[1]);
#endif /* UNUSED */
  }
#endif /* LWIP_DNS */

  /*
   * Check that the peer is allowed to use the IP address it wants.
   */
  if (ho->hisaddr != 0) {
    u32_t addr = lwip_ntohl(ho->hisaddr);
    if ((addr >> IP_CLASSA_NSHIFT) == IP_LOOPBACKNET || IP_MULTICAST(addr) ||
        IP_BADCLASS(addr)
    /*
     * For now, consider that PPP in server mode with peer required
     * to authenticate must provide the peer IP address, reject any
     * IP address wanted by peer different than the one we wanted.
     */
#if PPP_SERVER && PPP_AUTH_SUPPORT
        || (pcb->settings.auth_required && wo->hisaddr != ho->hisaddr)
#endif /* PPP_SERVER && PPP_AUTH_SUPPORT */
    ) {
      ppp_error(
          ("Peer is not authorized to use remote address %I", ho->hisaddr));
      ipcp_close(pcb, "Unauthorized remote IP address");
      return;
    }
  }
#if 0  /* Unused */
    /* Upstream checking code */
    if (ho->hisaddr != 0 && !auth_ip_addr(f->unit, ho->hisaddr)) {
	ppp_error(("Peer is not authorized to use remote address %I", ho->hisaddr));
	ipcp_close(f->unit, "Unauthorized remote IP address");
	return;
    }
#endif /* Unused */

#if VJ_SUPPORT
  /* set tcp compression */
  sifvjcomp(pcb, ho->neg_vj, ho->cflag, ho->maxslotindex);
#endif /* VJ_SUPPORT */

#if DEMAND_SUPPORT
  /*
   * If we are doing dial-on-demand, the interface is already
   * configured, so we put out any saved-up packets, then set the
   * interface to pass IP packets.
   */
  if (demand) {
    if (go->ouraddr != wo->ouraddr || ho->hisaddr != wo->hisaddr) {
      ipcp_clear_addrs(f->unit, wo->ouraddr, wo->hisaddr,
                       wo->replace_default_route);
      if (go->ouraddr != wo->ouraddr) {
        ppp_warn(("Local IP address changed to %I", go->ouraddr));
        script_setenv("OLDIPLOCAL", ip_ntoa(wo->ouraddr), 0);
        wo->ouraddr = go->ouraddr;
      } else
        script_unsetenv("OLDIPLOCAL");
      if (ho->hisaddr != wo->hisaddr && wo->hisaddr != 0) {
        ppp_warn(("Remote IP address changed to %I", ho->hisaddr));
        script_setenv("OLDIPREMOTE", ip_ntoa(wo->hisaddr), 0);
        wo->hisaddr = ho->hisaddr;
      } else
        script_unsetenv("OLDIPREMOTE");

      /* Set the interface to the new addresses */
      mask = get_mask(go->ouraddr);
      if (!sifaddr(pcb, go->ouraddr, ho->hisaddr, mask)) {
#if PPP_DEBUG
        ppp_warn(("Interface configuration failed"));
#endif /* PPP_DEBUG */
        ipcp_close(f->unit, "Interface configuration failed");
        return;
      }

      /* assign a default route through the interface if required */
      if (ipcp_wantoptions[f->unit].default_route)
        if (sifdefaultroute(pcb, go->ouraddr, ho->hisaddr,
                            wo->replace_default_route))
          default_route_set[f->unit] = 1;

#if 0  /* UNUSED - PROXY ARP */
	    /* Make a proxy ARP entry if requested. */
	    if (ho->hisaddr != 0 && ipcp_wantoptions[f->unit].proxy_arp)
		if (sifproxyarp(pcb, ho->hisaddr))
		    proxy_arp_set[f->unit] = 1;
#endif /* UNUSED - PROXY ARP */
    }
    demand_rexmit(PPP_IP, go->ouraddr);
    sifnpmode(pcb, PPP_IP, NPMODE_PASS);

  } else
#endif /* DEMAND_SUPPORT */
  {
    /*
     * Set IP addresses and (if specified) netmask.
     */
    mask = get_mask(go->ouraddr);

#if !(defined(SVR4) && (defined(SNI) || defined(__USLC__)))
    if (!sifaddr(pcb, go->ouraddr, ho->hisaddr, mask)) {
#if PPP_DEBUG
      ppp_warn(("Interface configuration failed"));
#endif /* PPP_DEBUG */
      ipcp_close(f->pcb, "Interface configuration failed");
      return;
    }
#endif

    /* bring the interface up for IP */
    if (!sifup(pcb)) {
#if PPP_DEBUG
      ppp_warn(("Interface failed to come up"));
#endif /* PPP_DEBUG */
      ipcp_close(f->pcb, "Interface configuration failed");
      return;
    }

#if (defined(SVR4) && (defined(SNI) || defined(__USLC__)))
    if (!sifaddr(pcb, go->ouraddr, ho->hisaddr, mask)) {
#if PPP_DEBUG
      ppp_warn(("Interface configuration failed"));
#endif /* PPP_DEBUG */
      ipcp_close(f->unit, "Interface configuration failed");
      return;
    }
#endif
#if DEMAND_SUPPORT
    sifnpmode(pcb, PPP_IP, NPMODE_PASS);
#endif /* DEMAND_SUPPORT */

#if 0  /* UNUSED */
	/* assign a default route through the interface if required */
	if (wo->default_route)
	    if (sifdefaultroute(pcb, go->ouraddr, ho->hisaddr,
		    wo->replace_default_route))
		    pcb->default_route_set = 1;
#endif /* UNUSED */

#if 0  /* UNUSED - PROXY ARP */
	/* Make a proxy ARP entry if requested. */
	if (ho->hisaddr != 0 && wo->proxy_arp)
	    if (sifproxyarp(pcb, ho->hisaddr))
		pcb->proxy_arp_set = 1;
#endif /* UNUSED - PROXY ARP */

    wo->ouraddr = go->ouraddr;

    ppp_notice(("local  IP address %I", go->ouraddr));
    if (ho->hisaddr != 0)
      ppp_notice(("remote IP address %I", ho->hisaddr));
#if LWIP_DNS
    if (go->dnsaddr[0])
      ppp_notice(("primary   DNS address %I", go->dnsaddr[0]));
    if (go->dnsaddr[1])
      ppp_notice(("secondary DNS address %I", go->dnsaddr[1]));
#endif /* LWIP_DNS */
  }

#if PPP_STATS_SUPPORT
  reset_link_stats(f->unit);
#endif /* PPP_STATS_SUPPORT */

  np_up(pcb, PPP_IP);
  pcb->ipcp_is_up = 1;

#if PPP_NOTIFY
  notify(ip_up_notifier, 0);
#endif /* PPP_NOTIFY */
#if 0  /* UNUSED */
    if (ip_up_hook)
	ip_up_hook();
#endif /* UNUSED */
}

/*
 * ipcp_down - IPCP has gone DOWN.
 *
 * Take the IP network interface down, clear its addresses
 * and delete routes through it.
 */
static void ipcp_down(fsm *f) {
  ppp_pcb *pcb = f->pcb;
  ipcp_options *ho = &pcb->ipcp_hisoptions;
  ipcp_options *go = &pcb->ipcp_gotoptions;

  IPCPDEBUG(("ipcp: down"));
#if PPP_STATS_SUPPORT
  /* XXX a bit IPv4-centric here, we only need to get the stats
   * before the interface is marked down. */
  /* XXX more correct: we must get the stats before running the notifiers,
   * at least for the radius plugin */
  update_link_stats(f->unit);
#endif /* PPP_STATS_SUPPORT */
#if PPP_NOTIFY
  notify(ip_down_notifier, 0);
#endif /* PPP_NOTIFY */
#if 0  /* UNUSED */
    if (ip_down_hook)
	ip_down_hook();
#endif /* UNUSED */
  if (pcb->ipcp_is_up) {
    pcb->ipcp_is_up = 0;
    np_down(pcb, PPP_IP);
  }
#if VJ_SUPPORT
  sifvjcomp(pcb, 0, 0, 0);
#endif /* VJ_SUPPORT */

#if PPP_STATS_SUPPORT
  print_link_stats(); /* _after_ running the notifiers and ip_down_hook(),
                       * because print_link_stats() sets link_stats_valid
                       * to 0 (zero) */
#endif                /* PPP_STATS_SUPPORT */

#if DEMAND_SUPPORT
  /*
   * If we are doing dial-on-demand, set the interface
   * to queue up outgoing packets (for now).
   */
  if (demand) {
    sifnpmode(pcb, PPP_IP, NPMODE_QUEUE);
  } else
#endif /* DEMAND_SUPPORT */
  {
#if DEMAND_SUPPORT
    sifnpmode(pcb, PPP_IP, NPMODE_DROP);
#endif /* DEMAND_SUPPORT */
    sifdown(pcb);
    ipcp_clear_addrs(pcb, go->ouraddr, ho->hisaddr, 0);
#if LWIP_DNS
    cdns(pcb, go->dnsaddr[0], go->dnsaddr[1]);
#endif /* LWIP_DNS */
  }
}

/*
 * ipcp_clear_addrs() - clear the interface addresses, routes,
 * proxy arp entries, etc.
 */
static void ipcp_clear_addrs(ppp_pcb *pcb, u32_t ouraddr, u32_t hisaddr,
                             u8_t replacedefaultroute) {
  LWIP_UNUSED_ARG(replacedefaultroute);

#if 0  /* UNUSED - PROXY ARP */
    if (pcb->proxy_arp_set) {
	cifproxyarp(pcb, hisaddr);
	pcb->proxy_arp_set = 0;
    }
#endif /* UNUSED - PROXY ARP */
#if 0  /* UNUSED */
    /* If replacedefaultroute, sifdefaultroute will be called soon
     * with replacedefaultroute set and that will overwrite the current
     * default route. This is the case only when doing demand, otherwise
     * during demand, this cifdefaultroute would restore the old default
     * route which is not what we want in this case. In the non-demand
     * case, we'll delete the default route and restore the old if there
     * is one saved by an sifdefaultroute with replacedefaultroute.
     */
    if (!replacedefaultroute && pcb->default_route_set) {
	cifdefaultroute(pcb, ouraddr, hisaddr);
	pcb->default_route_set = 0;
    }
#endif /* UNUSED */
  cifaddr(pcb, ouraddr, hisaddr);
}

/*
 * ipcp_finished - possibly shut down the lower layers.
 */
static void ipcp_finished(fsm *f) {
  ppp_pcb *pcb = f->pcb;
  if (pcb->ipcp_is_open) {
    pcb->ipcp_is_open = 0;
    np_finished(pcb, PPP_IP);
  }
}

#if 0  /* UNUSED */
/*
 * create_resolv - create the replacement resolv.conf file
 */
static void
create_resolv(peerdns1, peerdns2)
    u32_t peerdns1, peerdns2;
{

}
#endif /* UNUSED */

#if PRINTPKT_SUPPORT
/*
 * ipcp_printpkt - print the contents of an IPCP packet.
 */
static const char *const ipcp_codenames[] = {"ConfReq", "ConfAck", "ConfNak",
                                             "ConfRej", "TermReq", "TermAck",
                                             "CodeRej"};

static int ipcp_printpkt(const u_char *p, int plen,
                         void (*printer)(void *, const char *, ...),
                         void *arg) {
  int code, id, len, olen;
  const u_char *pstart, *optend;
#if VJ_SUPPORT
  u_short cishort;
#endif /* VJ_SUPPORT */
  u32_t cilong;

  if (plen < HEADERLEN)
    return 0;
  pstart = p;
  GETCHAR(code, p);
  GETCHAR(id, p);
  GETSHORT(len, p);
  if (len < HEADERLEN || len > plen)
    return 0;

  if (code >= 1 && code <= (int)LWIP_ARRAYSIZE(ipcp_codenames))
    printer(arg, " %s", ipcp_codenames[code - 1]);
  else
    printer(arg, " code=0x%x", code);
  printer(arg, " id=0x%x", id);
  len -= HEADERLEN;
  switch (code) {
  case CONFREQ:
  case CONFACK:
  case CONFNAK:
  case CONFREJ:
    /* print option list */
    while (len >= 2) {
      GETCHAR(code, p);
      GETCHAR(olen, p);
      p -= 2;
      if (olen < 2 || olen > len) {
        break;
      }
      printer(arg, " <");
      len -= olen;
      optend = p + olen;
      switch (code) {
      case CI_ADDRS:
        if (olen == CILEN_ADDRS) {
          p += 2;
          GETLONG(cilong, p);
          printer(arg, "addrs %I", lwip_htonl(cilong));
          GETLONG(cilong, p);
          printer(arg, " %I", lwip_htonl(cilong));
        }
        break;
#if VJ_SUPPORT
      case CI_COMPRESSTYPE:
        if (olen >= CILEN_COMPRESS) {
          p += 2;
          GETSHORT(cishort, p);
          printer(arg, "compress ");
          switch (cishort) {
          case IPCP_VJ_COMP:
            printer(arg, "VJ");
            break;
          case IPCP_VJ_COMP_OLD:
            printer(arg, "old-VJ");
            break;
          default:
            printer(arg, "0x%x", cishort);
          }
        }
        break;
#endif /* VJ_SUPPORT */
      case CI_ADDR:
        if (olen == CILEN_ADDR) {
          p += 2;
          GETLONG(cilong, p);
          printer(arg, "addr %I", lwip_htonl(cilong));
        }
        break;
#if LWIP_DNS
      case CI_MS_DNS1:
      case CI_MS_DNS2:
        p += 2;
        GETLONG(cilong, p);
        printer(arg, "ms-dns%d %I", (code == CI_MS_DNS1 ? 1 : 2),
                htonl(cilong));
        break;
#endif /* LWIP_DNS */
#if 0  /* UNUSED - WINS */
	    case CI_MS_WINS1:
	    case CI_MS_WINS2:
	        p += 2;
		GETLONG(cilong, p);
		printer(arg, "ms-wins %I", lwip_htonl(cilong));
		break;
#endif /* UNUSED - WINS */
      default:
        break;
      }
      while (p < optend) {
        GETCHAR(code, p);
        printer(arg, " %.2x", code);
      }
      printer(arg, ">");
    }
    break;

  case TERMACK:
  case TERMREQ:
    if (len > 0 && *p >= ' ' && *p < 0x7f) {
      printer(arg, " ");
      ppp_print_string(p, len, printer, arg);
      p += len;
      len = 0;
    }
    break;
  default:
    break;
  }

  /* print the rest of the bytes in the packet */
  for (; len > 0; --len) {
    GETCHAR(code, p);
    printer(arg, " %.2x", code);
  }

  return p - pstart;
}
#endif /* PRINTPKT_SUPPORT */

#if DEMAND_SUPPORT
/*
 * ip_active_pkt - see if this IP packet is worth bringing the link up for.
 * We don't bring the link up for IP fragments or for TCP FIN packets
 * with no data.
 */
#define IP_HDRLEN 20 /* bytes */
#define IP_OFFMASK 0x1fff
#ifndef IPPROTO_TCP
#define IPPROTO_TCP 6
#endif
#define TCP_HDRLEN 20
#define TH_FIN 0x01

/*
 * We use these macros because the IP header may be at an odd address,
 * and some compilers might use word loads to get th_off or ip_hl.
 */

#define net_short(x) (((x)[0] << 8) + (x)[1])
#define get_iphl(x) (((unsigned char *)(x))[0] & 0xF)
#define get_ipoff(x) net_short((unsigned char *)(x) + 6)
#define get_ipproto(x) (((unsigned char *)(x))[9])
#define get_tcpoff(x) (((unsigned char *)(x))[12] >> 4)
#define get_tcpflags(x) (((unsigned char *)(x))[13])

static int ip_active_pkt(pkt, len)
u_char *pkt;
int len;
{
  u_char *tcp;
  int hlen;

  len -= PPP_HDRLEN;
  pkt += PPP_HDRLEN;
  if (len < IP_HDRLEN)
    return 0;
  if ((get_ipoff(pkt) & IP_OFFMASK) != 0)
    return 0;
  if (get_ipproto(pkt) != IPPROTO_TCP)
    return 1;
  hlen = get_iphl(pkt) * 4;
  if (len < hlen + TCP_HDRLEN)
    return 0;
  tcp = pkt + hlen;
  if ((get_tcpflags(tcp) & TH_FIN) != 0 && len == hlen + get_tcpoff(tcp) * 4)
    return 0;
  return 1;
}
#endif /* DEMAND_SUPPORT */

#endif /* PPP_SUPPORT && PPP_IPV4_SUPPORT */
